Stabilized fuel oil



Patented Oct. 28, 1941 UNITED STATES PATENT OFFICE 2,261,003 STABILIZEDFUEL on.

Eugene T. Scafe, Woodbury, N. J., assignor to Socony-Vaeuum Oil Company,Incorporated,

New York, N. Y., a corporation of New York No Drawing. ApplicationDecember 5, 1939,

Serial No. 307,604

4 Claims. Light fuel oils, such as the No. 2 and No. 3

grades produced for and used in uses such as deterioration in storage,possibly due to the mild but prolonged oxidizing conditions of suchstorage. The deterioration results in the formation of sludge orsediment, which if not removed, plugs filter screens, orifices, andother parts of the equipment used in burning such fuel. Even when, aftersome storage, all visible sediment is removed from such oils, othersediment continues to form.

This invention is directed to the provision of 'such a fuel oil,relatively stable against the formation of such sediments and sludges.

This invention has for its object the provision of light fuel oilscontaining inhibitive materials capable of preventing the formation ofsludge and/or sediment in such oil, under the conditions of use usuallyencountered.

To enable understanding of this invention, there is first defined thetype of fuel oil with which it is concerned, by way of thefollowingexample, showing properties of atypical #3" fuel oil.

1 Untreated #3 fuel oil Gravity A. P. I Distillation, A. S. 'I. M,15 B.P

Recovery permnt Residue percent 2 Loss percent" Pour point F ---30 Flashpoint P. M. F 156 B. S. & W

Kinematic visc. 100 "F 1.08

Aniline cloud point, F 112. 0

Kauni-butanol No t3. 5

Neutralization numbe 0.07

r Ash of bottoms (percent wt.)

While the above oil is an untreated oil, many of these oils aretreated," that is have been treated with 5 pounds per barrel of 66 B.sulphuric acid, followed by water washing and neutralizing. Thistreating has little eflect upon physical properties, but serves toreduce the tendency to slud n sediment formation, etc.

This invention is based upon the discovery that the formation of sludgeand sediment under normal storage conditions may be prevented C9inhibition of sediment to the degree noted theresubstantially by theaddition to such an oil of small amount of di-cyclohexyl amine.

For example, the effectiveness of such addition may be shown by thefollowing tabulation of data:

Table I Time before appearance of sediment in days. Inhibitorconcentration,

08% sulphuric acid pounds percent weight per 42 gallon bbl.

2 6 6 6 4 6 6 6 6 4 11 11 12 12 1 8 l1 .ll 11 In the above tests, alight fuel oil, both untreated, and treated with various amounts ofacid, as shown in the first column, then doped with varying amounts ofinhibitor, as shown by columns 3-7 inclusive, was compared with anundoped 011, shown by column 2, in an accelerated test wherein samplesof the oil were held at 160 F. in the presence of iron, while exposed tothe atmosphere. Reading the first horizontal line, it is found that inan untreated oil which formed sediment when undoped in 2 days, even 0.05percent by weight of the inhibitor, prevented the appearance of sedimentuntil the elapse of 6 days. Similarly, in line 3 of Table I, where theoil was treated with 5#/bbl. of acid, sediment formed in the undoped oilin 4 days, while 0.01% by weight of the inhibitor prevented itsappearance until the eleventh day.

As shown in Table II below, while quite small amounts of inhibitor delaythe formation of sediment, they do not greatly reduce the total amounteventually formed,but larger amounts of inhibitormarkedly reduce theamount formed,

particularly with heavily acid treated oils.

The above test! were conducted as an accelerated aging test in the samemanner as before, by exposing oil to storage at F., exposed toatmosphere, in the presence of iron, except the test was continued for20 days.

; These accelerated tests are quite severe, and

in would practically mean complete inhibition of sedimentation for thenormal period of storage at normal temperature conditions.

In general, since the prime necessity is that of preventing theappearance of sediment in the oil under the normal conditions of storageat atmospheric temperature during the normal time which elapses prior toits use, the lower concentrations are the more economically useful andwhile from about 0.01% to 0.10% by weight may,

tors such as for example alpha-naphthol andother recognized gasolineinhibitors are not eflective for the present purpose.

I claim:

1. An unrefined light fuel oil of gas oil nature inhibited against theformation 5: sediment by oxidation under conditions of normal storage bythe addition thereto of smallamounts of di-cyclohexylamine.

2. An unrefined light fuel oil of gas oil nature which has been treatedwith sulphuric acid, and inhibited against the formation of sediment byoxidation under conditions of normal storage by the addition thereto ofsmall amounts of di-cyclohexyl amine.

3. An unrefined light fuel oil of gas oil nature inhibited against theformation of sediment by oxidation under conditions of normal storage bythe addition thereto 01' from about 0.01 to about 0.10 percent by weightof di-cyclohexyl amine.

4. An unrefined light fuel oil of gas oil nature inhibited against theformation of sediment by oxidation underconditions of normal storage bythe addition thereto of from about 0.01 to about 0.02 percent by weightof di-cyclohexyl amine.

EUGENE T. SCAFE.

